121 - 4 - A
Card Set Information
121 - 4 - A
Review of Signaling System Organization
All signaling systems do what?
Allow communication between two cells
What are the basic molecular components of signaling systems?
Signal Transduction Pathway
Where do ligands come from?
Signaling Cell (cell they originated from)
What are ligands also known as?
Primary Signal molecule
Target Cells are known as?
Primary Responding Molecule
A primary responding molecule (target cell) that is on a cell that is receiving communication is called?
Signal transduction pathway is also known as?
The second messenger cascade
In a receiving cell, the intracellular series of signal transducing molecules are called?
Signal transduction pathway (second messager cascade)
Effector mechanism is also known as?
In receiving cell, the molecular event that the signal is meant to produce is called?
Effector mechanism (Target mechanism)
In an aqueous organism, what are the two ways ligand can access their receptor on the downstream cell?
(1) Ligands secrete into the fluids of the body
(2) ligands can transduce (transfer) information through cellular contact
What are the three aqueous environments that cells can secrete ligands?
Blood -- Endocrine Ligands
Local Fluids -- Paracrine Ligands
Neuronal Synapse -- neurotransmitter
Ligands dispersed into the blood...
can reach all cell type in the body
Ligands dispersed into the local fluids...
reach a selected few cell types within a tissue
Ligands dispersed into a neuronal synapse...
can reach as few as a single cell
Signaling through cellular contact can use either?
Soluble Ligands ( in the form of second messenger molecules)
Signal Transduction Pathway is?
Are used by cells to convert chemical messages to cellular action
Closely related cells can communicate... how?
Without secretion of ligands into the extracellular space, they are able to communicate by directly sharing second messenger molecules in their cytosol through gap junctions
Immobilized ligands on the surface of cells or in the extracellular matrix of tissues can what?
bind to downstream cell receptors and function just like soluble ligands
All cells build their ability to respond to specific signals into their phenotype by
second messenger cascades (signal transduction (transfer) pathway)
that they express
The cellular response to a single or multiple signals is...
hard-wired and can only change if there is a change in phenotype.
What are the two major classes of
in the cells of multicellular organisms?
(1) The ones that are in the transmembrane in the plasma membrane will respond to water soluble ligands
(2) The ones inside of the cell will respond to ligands that are able pass the plasma membrane
Why are intracellular second messenger cascades are complex?
in order for the cell to control them better and allowing multiple signaling pathways to communicate inside the cell
One or more target mechanism are what?
hard-wired to every signal cascade and can only be changed if phenotype changed